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problem with restriction digest - I have an insert, but no vector.... (Jan/24/2008 )

I am trying to clone an insert into a Pet-30 vector. I generated the insert by PCR adding on NdeI/XhoI ends. I cleaned up my pcr using the Qiaquick PCR purification. I digested my product (using Nde/XhoI) for about 3 hrs @37 deg. When I run the digest on a gel, I see my insert (which appears to be the right size), but not the vector. Help?

-biosci02-

What vector?
After you purified your pcr product you'll have hardly any of the plasmid you used to amplify that fragment from...
Maybe I got things wrong....

-Ambrósio-

You would have too little of the DNA template to actually see it when you run a gel.

-scolix-

werll did you mean you can't see the pet 30 vector after preparation ?
what's the starting amount of vector DNA ? did you load 1µl of undigested vector too ?

-fred_33-

i have the opposite results with u
i can see my vector but cannot find the insert...

-swingsinsky-

QUOTE (swingsinsky @ Feb 7 2008, 02:51 PM)
i have the opposite results with u
i can see my vector but cannot find the insert...



how much of the miniprep DNA did you digest? You need to have a particular amount of DNA in order to see fragments which are being digested out.

eg. if your vector + insert is 5kb and your insert is 500bps. If you digest 100ng of this, you will get ~90 ng of vector and 10ng of insert. And 10ng might be easily missed because of the low concentration.

-scolix-